Alewife:

In my previous life, I was a graduate student in the Laboratory for Computer Science at
the Massachusetts Institute of
Technology. I was involved in both the hardware and software
building efforts for the MIT Alewife Machine, a cache-coherent
distributed-memory multiprocessor. The Alewife Project investigated
several interesting architectural features for large-scale distributed
shared memory machines, including the integration of message passing
and shared memory communication models, software-extended
directory-based cache coherence, block multithreading, and full-empty
bits for fine-grain synchronization.

Below is a picture of an Alewife node. For more details, check out
the Alewife home
page.